1. Technical Field
The present invention relates to a technology of ejecting liquid such as ink.
2. Related Art
Various technologies of ejecting liquid such as ink onto a printing medium such as printing paper have been proposed from the past. For example, JP-A-2005-153243 discloses a liquid ejecting head in which a nozzle plate is disposed on the surface of a flow path forming substrate. A plurality of nozzles are formed on the nozzle plate and the liquid filled in a pressure chamber formed by the flow path forming substrate is ejected from the nozzles.
In the configuration of JP-A-2005-153243, the flow path forming substrate or the nozzle plate having a flat plate shape is disposed to intersect a liquid ejecting direction, and therefore, the area of the head (the area of a liquid ejecting surface of the liquid ejecting head) seen from the printing medium side is large. Accordingly, there is a problem in that it is difficult to dispose the plurality of nozzles at high density (to make a high resolution printing image). In addition, in the configuration in which a plurality of liquid ejecting heads are arranged, the plurality of nozzles are distributed over a wide range and therefore, there is also a problem in that it is difficult to make the interval between the liquid ejecting surface and the printing medium uniform over the plurality of heads (the image quality will be degraded).
On the other hand, in the technology of JP-A-2001-063044, an ink jet head in which a pressure chamber filled with ink is formed between a first substrate and a second substrate that have a flat plate shape is disclosed. A nozzle plate is disposed on the side surfaces of the first substrate and the second substrate and the ink in the pressure chamber is ejected from a nozzle formed on the nozzle plate. In the configuration of JP-A-2001-063044, the first substrate and the second substrate are disposed to be parallel to an ink ejecting direction. Therefore, the area of the head seen from the printing medium side can be decreased compared to the configuration of JP-A-2005-153243.
However, in the opening of the nozzle, the ink is thickened due to the contact with the outside air. In the technology of JP-A-2001-063044, the distance between the opening of the nozzle and the pressure chamber is short, and therefore, there is a problem in that the thickening in the opening may easily influence the inside of the pressure chamber (the thickened ink in the opening may easily reach the inside of the pressure chamber). Since the ink in the pressure chamber is stirred by the increase or decrease of the pressure, the thickened ink having reached the inside of the pressure chamber is dispersed over a wide range. Therefore, in order to avoid the influence of the thickening, a process (flushing) of discharging a massive amount of ink is required.